The COPY  field  description  statement  copies  an  existing  record
 description  (a  template record) into the description of a new field
 (a COPY field).

Additional information available:

Syntax RulesUsage NotesExample

  o  You must assign a field name to a COPY field.   This  field  name
     can  be up to 31 characters from the set A-Z, 0-9, _, and $.  The
     first character must be a letter from A-Z, and the last character
     can  not  be  _ or $.  You can use alphabetic 8-bit characters in
     field names.

  o  The path name can be a full or a relative path name, and it  must
     be  the path name of an existing CDD record description.  You can
     specify an absolute version number with the path name.

  o  The COPY  field  description  statement  must  terminate  with  a
     period.

  o  The copy operation takes place when the new record  is  compiled,
     not when it is copied into a program.  When you modify a template
     record, you should recompile any record definitions that  contain
     COPY field descriptions copying the modified template record.

  o  The COPY field description statement copies a complete record,  a
     template record, into a single field.

  o  The COPY field description statement copies  the  description  of
     the template record as the description of the COPY field.  If the
     first subordinate field of the template record is  a  BIT  field,
     the first subordinate field of the COPY field begins on the first
     bit immediately following the preceding  field.   Otherwise,  the
     COPY  field  begins  on  the first byte immediately following the
     preceding field.  You can modify this starting position with  the
     ALIGNED clause

  o  If you specify an  absolute  version  number  in  the  path  name
     parameter,  CDDL  copies  the version of the template record with
     that version number each time you compile the record  description
     containing  the  COPY  field.   If  you  do not specify a version
     number, CDDL copies the highest version of  the  template  record
     each time you compile the record description.

  o  In the COPY field, the field name you assign replaces  the  field
     name  copied from the field description statement of the template
     record.

  o  When the CDDL compiler compiles a record definition containing  a
     COPY   field   description,   it  automatically  makes  an  entry
     documenting the  copy  operation  in  the  history  list  of  the
     template record, whether or not you use the /AUDIT qualifier.

 CDD$TOP.CORPORATE.ADDRESS_RECORD  defines  the  standard  format  for
 addresses.   You  can copy this field description into any new record
 requiring an address field.

 ADDRESS                 COPY FROM
                         CDD$TOP.CORPORATE.ADDRESS_RECORD.